Low density microcellular foams

Patent · Wed Dec 31 23:00:00 EST 1986

OSTI ID:866279

Aubert, James H ^[1]; Clough, Roger L ^[1]; Curro, John G ^[2]; Quintana, Carlos A ^[1]; Russick, Edward M ^[1]; Shaw, Montgomery T ^[3]

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1. Albuquerque, NM
2. Placitas, NM
3. Mansfield Center, CT

Low density, microporous polymer foams are provided by a process which comprises forming a solution of polymer and a suitable solvent followed by rapid cooling of the solution to form a phase-separated system and freeze the phase-separated system. The phase-separated system comprises a polymer phase and a solvent phase, each of which is substantially continuous within the other. The morphology of the polymer phase prior to and subsequent to freezing determine the morphology of the resultant foam. Both isotropic and anisotropic foams can be produced. If isotropic foams are produced, the polymer and solvent are tailored such that the solution spontaneously phase-separates prior to the point at which any component freezes. The morphology of the resultant polymer phase determines the morphology of the resultant foam and the morphology of the polymer phase is retained by cooling the system at a rate sufficient to freeze one or both components of the system before a change in morphology can occur. Anisotropic foams are produced by forming a solution of polymer and solvent that will not phase separate prior to freezing of one or both components of the solution. In such a process, the solvent typically freezes before phase separation occurs. The morphology of the resultant frozen two-phase system determines the morphology of the resultant foam. The process involves subjecting the solution to essentially one-dimensional cooling. Means for subjecting such a solvent to one-dimensional cooling are also provided. Foams having a density of less than 0.1 g/cc and a uniform cell size of less than 10 .mu.m and a volume such that the foams have a length greater than 1 cm are provided.

• Research Organization: AT & T CORP
• DOE Contract Number: AC04-76DP00789
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4673695
• OSTI ID: 866279
• Country of Publication: United States
• Language: English

Related Subjects

/521/210/264/
10
anisotropic
cc
cell
cell size
cellular foam
change
cm
component
components
comprises
comprises forming
continuous
cooling
density
density microcellular
determine
determines
essentially
foam
foams
followed
form
forming
freeze
freezes
freezing
frozen
involves
involves subjecting
isotropic
length
means
microcellular
microcellular foam
microcellular foams
microporous
microporous polymer
morphology
occur
occurs
one-dimensional
phase
phase separate
phase separation
phase-separated
phase-separates
polymer
polymer foam
polymer phase
porous polymer
prior
process
process involves
produced
provided
rapid
rapid cooling
rate
rate sufficient
resultant
retained
separate
separation
separation occurs
size
solution
solvent
solvent followed
solvent phase
spontaneously
subjecting
subsequent
substantially
substantially continuous
sufficient
suitable
suitable solvent
tailored
two-phase
typically
uniform
volume